Vacuum lightning-arrester.



F. S. CHAPMAN. VACUUM LIGHTNING ARRESTBR.

APPLICATION FILED JULY 9, 1912.

Patented July 28, 1914 www @.11 www.

2 SHEETS-SHEET 1.

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Patnted July 28, 1914.

2 SHEETS-SHEBT 2.

UNITED sTATEs PATENT oEErcE.

EnANx'fsrENcEE GHAPMAN, or ToLEno, omo, AssroNon To THE NATIONAL ELECTRIC srEcrALTY COMPANY, or TOLEDO, omo, A conronATIoN 0E omo.

VACUUM LIGHTNINAEEEsTEB..

Patented July 2s, 1914.

Application llled July 9, 1912. :Serial No. 708,445..

resters, of which the following is a specification.

My invention relates to devices for protectin electrical apparatus from the destructive e ects of high potential currents or discharges, these devices being commonly called lightning 'arrestersg and the invention hasv for its primary object to'provide a new and improved device of this sort, designed more particularly for use on circuits normally carrying currents of relativel high potential, for example, four hun red volts or over, although it will be understood that the invention is not to be considered as limited in respect to the voltages employed.

If a vacuum lightnin arrester consisting of two electrodes place side by side in an evacuated vessel is used on a circuit which normally carries a heavy current and such circuit becomes affected by a static discharge of suliicient, strength to cause a discharge across the ga between the electrodes, the arc so forme has a tendencv to ionize or otherwise affect the region a ut the electrodes so that a path of low resistance is Lformed between the electrodes over which the normal current will continue to liow after the static or high potential discharge is at an end. This, of course, grounds the line throu h the arrester and furthermore, often resu ts in the destruction of the arrester; 'lightning arresters as ordinarily con. structed being capable of taking care of a high potential discharge of short duration but incapable of withstanding the effects of a continued discharge of a much lower voltave.

-bThe present invention provides a vacuum lightning arrester in which one oi-both of the electrodes are inclosed or partially inclosed within shields formed of material of a character to withstand the intense heat roduced by the static discharge, the shields Being arranged so that the discharge is comypelled to take an angular path, instead of going in a direct line from electrode to electrode. 'Ihe normal current is not capable of following this angular path and hence. one

o f the chief causes of injury to or destruction of the ,arrester is eliminated. Furthermore, the shields are larranged so that they protect the'walls of the vessel, the vessel bel ing ordinarily made of lass, from the intense -heat produced w en the discharge ltakes place.` The heat produced in some cases is sufficient to crack the glass or melt it. The invention has for further objects such other new and improved constructions, arrangements and deviceslrelating to li lhtnin arresters as will be hereinafter descri ed an claimed. y

The invention is illustrated, in certain preferred embodiments, in the accompanying drawings, whcreini of one preferred form ofthe invention; Fig. 2, a plan viewof the same; Fig. 3, a sectional view taken online 3--3 of Fig. 2, looking inthe direction ofthe arrows; Fig. 4, a sectional .view taken on line 4 4 of Fig. 1, looking in the direction of the arrows, and Fig. 5, a sectional view, with arts in elevation, illustrating a modified` orm of arrester.

Like characters of reference indicate like parts in the several figures of the drawings. Referring first to Figs. 1 to 4 inclusive, 10 designates a glass tube or vessel formed at each end with a bend 11 and with the inwardly projecting, preferably integrally formed stem 12. lThis' vessel is evacuated to the proper degree and is mounted on any suitable form of support. I have shown for this purpose a porcelain block 13 formed with bosses 14 in which the bent extremities of the vessel-are seated. On each stem 12 is a base 15 of refractory, non-conducting material, preferably porcelain, which I have found convenient and desirable to secure to the stem by means of a body of asbestos cement 16 which is thoroughly dried by baking at a temperature of about five hundred degrees Fahrenheit.. On the bases 15 are placed electrodes 17, preferably made of carbon, which may be cemented to the bases by bodies of asbestos cement 18. On each of the bases is `located a preferably cylindrical shield 19 of some refractory, non-conducting material. These cylinders may be made of porcelain and integral, in each case, with the bases. The cylindrical shields 1'9 extend above the under side of the main body of the '570 Figure 1 is a longitudinal sectional view tube 10 and are open at the top. Wires20 sealed through the stems and passlng through the bodies of cement, porcelain bases and into the electrodes, connect the electrodes, respectively, with the external wires 2l and 22, one leading to the line 23 to be protected, and the other to a grounded line 24.

1n order that the arrester may be readily removed and replaced without disturbing the connections of the line and ground wires 23 and 24 I make use of the following devices and arrangements: 25 is a xed base having a binding post 26, to which the grounded wire 24 is connected, and a binding post 2T to which the line wire 23 is connected. 28 is a spring jack secured in a recess in the upper face of the block 25 by means ot' the bolt 29 which is electrically connected by a wire 30 with the binding` post 26. A clip 31 is secured to the removable base 13 by a bolt 32 with which the wire 22 is in contact, the clip 3l being` adapted to engage the jack 28. A splice bar or link 33 is secured to the removable base 13 by a bolt 34 with which the wire 21 is in contact and extends over and is 'secured to the binding post 27 by means of a nut 35. By simply removing the nut 35 the base 13 supporting the lightning arrester may be removed from the fixed base or plug 25.

In F ig. 5 I have shownv a modified construction of arrester. 36 designates an evacuated glass vessel having somewhat the shape of the ordinary electric light bulb and formed with the inwardly projecting stem 37 on which is mounted, preferably by means of the body of asbestos cement 38,A

the porcelain base 39 supporting or formed -with the porcelain cylinder 40 within which is located one of the electrodes 41. The other electrode 42 is placed on the base outside of the cylinder 40. The vessel 36 has the familiar terminals 43 and 44, one of the leading-in wires being electrically connected to one of these terminals and the other wire 46 with the other terminal.

While I havev described my invention in certain .preferred embodiments it will be readily understood that modifications might be made without departure from the invention. Therefore I do not wish to be considered as limiting my invention to the particular constructions, arrangements and devices shown and described except so far as these particulars are made specifically limitations in certain of the claims herein.

I claim:

1. In a lightning arrester, the combination with an evacuated glass vessel having an inwardly projecting glass stem, a pair of electrodes within said vessel, a base of non-conducting, refractory material, a body of asbestos cement which unites the base to said stem, and a hollow element of nonconducting, refractory material on said base open at the top, one of said electrodes being arranged in said hollow element.

2. In a lightning arrester, the combination with an evacuated tube formed with a bend at one end, an electrode arranged in said bend, a second electrode at the other end of said tube, and a non-conducting, refractory shield arranged adjacent the first named electrode so as to prevent direct discharge between said electrodes and protect the wall of said vessel.

3. In a lightning arrester, the combination with an evacuated tube formed with a bend at one end, an electrode arranged in said bend, a second electrode at the other end of the tube, and a hollow, n0n-conducting, refractory element open at one end .which surrounds the first named electrode.

4. In a lightning arrester, the combination with an evacuated tube having a bend at each end, electrodes located in said bends, and non-conducting, refractory elements associated with said elements and'arranged so as to prevent a discharge in a direct line between the electrodes and to protectthe adjacent portions of the wall of said vessel.

5. In a lightning arrester, the combination with an evacuated tube having a bend at each end, electrodes located in'said bends, and hollow elements open, in each case, at one end and formed of non-conducting, refractory material which surrounds said elec` trodes, respectively.

6. In a lightning arrester, the combination with an evacuated tube formed at each end with a bend and an inwardly projecting stem, a base secured to each of said stems, electrodes mounted on said bases, and shields of non-conducting, refractory material arranged adjacent said electrodes respectively and between the same.

'7. In a lightning arrester, the combination with an evacuated tube formed at each end with a bend, and an inwardly projecting stem, a base secured to each of said stems, cylindrical shield members of nonconducting, refractory material 0n said bases, and electrodes located in said shield members.

8. In a lightning arrester, the combination with an evacuated vessel, of a pair of electrodes vtherein and a base member of non-conducti g material provided with a hollow cylin rical extension on one side thereof, one of said electrodes bein arranged within said hollow cylindrica extension.

9. In a lightning arrester, the combination with an evacuated vessel having an inwardly projecting stem, of a pair of electrodes, and a base member of non-conducting material mounted on said stem and provided with a hollow cylindrical extension on lone side thereof, one of said electrodes being arranged within said hollow cylindrical extension.

l0. A lightning arrester comprising an evacuated glass container, an electrode mounted therein, and a non-conducting, refractory shield substantially cylindrical in form which surrounds said electrode and is spaced away from the same and from the wall of the container so as to protect the latter from' the eect of the discharge through the arrester.

11. ln a lightning arrester, the combination with an evacuated vessel having an inwardly projecting stem, of a pair of electrodes, and a base member of non-conducting material mounted on said stem and provided with a hollow cylindrical extension on one side thereof, one of said electrodes being arranged within said hollow cylindrical extension and the other outside 0f the same.

12. A lightning arrester comprising an evacuated glass vessel formed with an inturned stem, a base member of refractory, non-conducting material arranged in said vessel transverse to the stem, a leading-in wire sealed through said stem and secured to said base, a body of refractory cement-itious material interposed between the vstem and the base, an electrode mounted on said base electrically connected with said leading-in wire, and a protecting shield of refractory material on said base surrounding the electrode.

13. A vacuum lightning arrester compris ing an evacuated glass vessel, a plurality of electrodes in said vessel, and means providing a protecting shield surrounding one or more of said electrodes and spaced away `from the same and from the wall of saidl vessel so as to protect the latter from the eHec-ts of the discharges between said electrodes.

le. A vacuum lightning arrester comprising a tubular evacuated glass vessel, electrodes mounted one at each end of said vessel, and means providing a protectingi shield surrounding said electrodes an spaced away from the same and from the Wall of said vessel so as to protect the latter from the effects of the discharges between said electrodes FRANK SPENCER CHAPMAN, Witnesses:

F. T. ROGERS, E. M. NEUHAUSEL. 

